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PubMed2002

Hyoid motion during swallowing: factors affecting forward and upward displacement.

During swallowing, the hyoid bone is described as moving first upward, then forward, then returning to the starting position. This study examined hyoid motion during swallowing of chewed solids and liquids. Barium videofluorography (VFG) was performed on 12 healthy volunteers eating 8-cc portions of various solid foods and drinking liquid. Hyoid position was measured frame-by-frame for 88 swallows relative to the occlusal plane of the upper teeth. The hyoid bone moved both upward and forward during swallowing, but upward displacement was sometimes very small. There was no correlation between the amplitudes of hyoid upward and forward displacements. The amplitude of upward displacement was highly variable, smaller for liquids than for solid foods (p <0.001), and, for solid foods, larger for the first swallow than for the second swallow (p = 0.02). The amplitude of forward displacement did not differ significantly between liquids and solids or between first and second swallows. We conclude that upward displacement of the hyoid bone in swallowing is related primarily to events in the oral cavity, while its forward displacement is related to pharyngeal processes, especially the opening of the upper esophageal sphincter.

Adult↗

PubMed2003

The effects of cervical bracing upon swallowing in young, normal, healthy volunteers.

The purpose of this study was to evaluate radiographically the effects of cervical bracing upon swallowing thin liquids and solid food in normal adults under three cervical bracing conditions. This was a prospective, repeated measures design study. Seventeen healthy adult volunteers between the ages of 30 and 50 were recruited from hospital staff. All subjects reported no previous history of swallowing difficulty or diseases that might affect swallowing. Subjects were radiographically observed swallowing thin liquids and solid food without cervical bracing and with three common cervical orthoses (Philadelphia collar, SOMI, and halo-vest brace). Order of bracing and type of bolus were randomized. Changes in swallowing function (point of initiation of swallow response, presence of pharyngeal residue, airway penetration, hyoid bone movement, diameter of oropharyngeal airway, and durational measurements) were analyzed by two independent raters. Eighty-two percent (14/17) of the subjects demonstrated radiographic changes under one or more of the bracing conditions. Forty-seven percent (8/17) of subjects demonstrated changes with point of initiation of the swallow response, 59% (10/17) demonstrated increased pharyngeal residue, and 23.5% (4/17) demonstrated changes with bolus flow with laryngeal penetration present. Aspiration did not occur under any of the bracing conditions. Changes noted in durational measurements for oral containment and total pharyngeal transit under the bracing conditions were not considered statistically significant. This study shows that cervical bracing does change swallowing physiology in normal healthy adults.

Adult↗

PubMed2003

Dysphagia in patients with nasopharyngeal cancer after radiation therapy: a videofluoroscopic swallowing study.

This study evaluated swallowing status and the factors influencing swallowing in patients with nasopharyngeal carcinoma (NPC) after radiation therapy. During the period from July 1995 to June 1999, this cross-sectional study used videofluoroscopic swallowing study (VFSS) to evaluate 184 NPC patients who had completed radiation therapy [113 cases had completed radiation therapy < or = 12 months prior to evaluation (acute group) and 71 cases had completed radiation therapy > 12 months prior to evaluation (chronic group)]. The numbers of patients with tumors in each of the four stages were as follows: 24 in stage I, 45 in stage II, 41 in stage III, and 74 in stage IV. Swallowing abnormalities of the acute and chronic groups were correlated with multiple variables, including gender, age, the stage of the tumor, use of either neoadjuvant chemotherapy or radiosensitizer, and radiation modality. The analytical results indicated that the chronic group had a significantly higher proportion of swallowing abnormalities. Radiation modality, chemotherapy, and tumor staging were not significantly associated with swallowing dysfunction. Trend analysis revealed a progressive deterioration of most parameters of swallowing function in this group of patients. These findings indicate that swallowing function continues to deteriorate over time, even many years after radiation therapy in patients with NPC. Our results indicate that the time elapsed since radiation therapy correlates with the severity of dysphagia in NPC patients.

Adolescent↗

PubMed2004

Awareness of dysphagia by patients following stroke predicts swallowing performance.

Patients' awareness of their disability after stroke represents an important aspect of functional recovery. Our study aimed to assess whether patient awareness of the clinical indicators of dysphagia, used routinely in clinical assessment, related to an appreciation of "a swallowing problem" and how this awareness influenced swallowing performance and outcome in dysphagic stroke patients. Seventy patients were studied 72 h post hemispheric stroke. Patients were screened for dysphagia by clinical assessment, followed by a timed water swallow test to examine swallowing performance. Patient awareness of dysphagia and its significance were determined by detailed question-based assessment. Medical records were examined at three months. Dysphagia was identified in 27 patients, 16 of whom had poor awareness of their dysphagic symptoms. Dysphagic patients with poor awareness drank water more quickly (5 ml/s vs. <1 ml/s, p = 0.03) and took larger volumes per swallow (10 ml vs. 6 ml, p = 0.04) than patients with good awareness. By comparison, neither patients with good awareness or poor awareness perceived they had a swallowing problem. Patients with poor awareness experienced numerically more complications at three months. Stroke patients with good awareness of the clinical indicators of dysphagia modify the way they drink by taking smaller volumes per swallow and drink more slowly than those with poor awareness. Dysphagic stroke patients, regardless of good or poor awareness of the clinical indicators of dysphagia, rarely perceive they have a swallowing problem. These findings may have implications for longer-term outcome, patient compliance, and treatment of dysphagia after stroke.

Aged↗

PubMed2004

Volume and rate of milk delivery as determinants of swallowing in an infant model animal (Sus scrofia).

The volume transported into the valleculae by the rhythmic tongue movements of suckling is considered the prime factor for initiating pharyngeal swallowing (the movement of milk out of the valleculae and through the pharynx to the esophagus). This study addressed the impact of variation in two factors on sucking (oral phase) and on swallowing (pharyngeal phase) in infant pigs, as a model for mammalian function: (1) the delivery of different-volume aliquots of milk and (2) the delivery of equal-sized aliquots at different frequencies. The number of sucks per second remained constant with change in both aliquot volume and change in the frequency of milk delivery. However, while the number of swallows per second remained constant as delivery volume increased, it increased as delivery frequency increased. Conversely, swallow volume increased with both increase in aliquot volume and in the frequency of delivery. Piglets consequently initiated pharyngeal swallows with a highly variable amount of milk in the valleculae. We conclude that volume is only one factor initiating the pharyngeal swallow. The sensory stimulation of milk delivery to the anterior oral cavity is also a factor in determining the frequency of swallows and the volume of milk per swallow.

Age Factors↗

PubMed2005

An acoustic profile of normal swallowing.

Cervical auscultation has been proposed as a technique to augment the clinical evaluation of dysphagia to improve its accuracy in the diagnosis of dysphagia. Before using cervical auscultation to reliably diagnose disordered swallowing, it is necessary to first acoustically characterize normal swallowing for comparison with dysphagic swallowing. Ninety-seven healthy adult participants consumed teaspoon boluses of various consistencies while the sounds of swallowing were recorded. Descriptive statistics were reported for measures of duration, intensity, and frequency of the acoustic swallowing signal. Correlations between the variables and between bolus consistencies were computed. Overall, results compared favorably with previous research. Significant correlations were found among several of the variables, including an increasing duration of the acoustic swallowing signal with increasing age and decreasing intensity of the signal with increasing age. None of the variables differed significantly as a function of gender. Of potential clinical relevance, significant correlations between bolus consistencies for the duration and intensity variables indicated relative similarities across bolus consistencies. Duration and intensity of the acoustic signal appeared to be the most reliable of the variables measured. These results could serve as a reference point for future studies into normal swallowing across multiple bolus consistencies and volumes and eventually be compared with disordered swallowing.

Acoustics↗

PubMed2006

Influences of thermal and gustatory characteristics on sensory and motor aspects of swallowing.

Two sets of experiments were conducted to examine the effects of two sensory modalities, temperature and taste, of foods on perceptual and motor aspects of swallowing in 20 young, healthy subjects (10 subjects for each experiment). A tasteless and odorless thickening agent was the basic testing material. The first experiment compared the swallowing of foods at four temperatures ranging from 5 degrees C to 50 degrees C. Food at 50 degrees C was more acceptable for swallowing than at 5 degrees C, 20 degrees C, or 35 degrees C. The suprahyoid muscles were less active during swallowing food at 50 degrees C compared with swallowing food at the other three temperatures. The second experiment compared foods with the five basic taste qualities (sweetness, saltiness, sourness, bitterness, and umami) with a tasteless food (dissolved in distilled water) to examine the influence of gustatory sensation. The sweet and tasteless foods were somewhat more acceptable for swallowing than the sour and bitter foods. However, none of the foods differentially altered the motor parameters of swallowing. Interactive influences of temperature and gustatory sensations of foods on swallowing are discussed.

Adult↗

PubMed2006

Measures of tongue function related to normal swallowing.

The availability of objective measures of tongue function presents a possible supplement to the clinical dysphagia evaluation. The purpose of this study was to improve our understanding of normal tongue physiology during swallowing and maximum isometric tasks, establish a preliminary database of tongue function variables, and determine if differences existed among the variables as a function of age, gender, or varied bolus consistency. Ninety subjects, divided into age and gender groups, participated in tasks that determined maximum isometric tongue pressure, mean tongue pressure during swallowing, and percentage of maximum isometric pressure used during swallowing. Descriptive statistics, correlations, and analyses of variance were computed to analyze the data. Results indicated that males had significantly higher maximum isometric pressures than females, and the youngest group had significantly higher maximum pressures than the oldest group. Mean swallowing pressures and percentage of maximum isometric pressures used during swallowing differed as a function of bolus type but did not differ as a function of age or gender. In addition, maximum isometric pressures were correlated with mean swallowing pressures, and mean swallowing pressures and percentage of maximum isometric pressures used during swallowing were correlated between consistencies.

Adult↗

PubMed2004

An experimental study of leaf swallowing in captive chimpanzees: insights into the origin of a self-medicative behavior and the role of social learning.

Chimpanzees in the wild swallow the rough hispid leaves of certain plant species as a means of physically expelling intestinal parasites. A plant with such a leaf texture was introduced in 36 trial sessions to a captive group of 11 healthy adult chimpanzees to investigate the possible origin and acquisition of leaf swallowing behavior. One male (housed separately from the group during testing) and one female, both captive born, spontaneously exhibited the behavior on their first trial without prior opportunity to observe others with this plant. Six other chimpanzees on their first trial displayed a phobic response to these leaves and rejected them entirely, while another two chewed and swallowed the leaves in a normal way. Four individuals eventually exhibited the behavior, after having approached and closely observed the leaf swallowing of the first female to exhibit the behavior in the group. Four of the six individuals that initially avoided the leaves never overcame their phobia toward this plant and were not in proximity to a chimpanzee performing leaf swallowing during test sessions. Individuals born to wild chimpanzee mothers were no more likely to perform the behavior than captive-reared group mates. These results suggest that the acquisition of this behavior is based in part on a propensity to fold and swallow rough, hispid leaves, but that the acquisition and spread of leaf swallowing within a group is likely to be socially influenced. This study provides support for the hypothesis that leaf swallowing originated in the wild from opportunistic feeding behavior and was later passed down in the form of a self-medicative behavioral tradition.

Animals↗

PubMed1991

Evidence that activation of N-methyl-D-aspartate (NMDA) and non-NMDA receptors within the nucleus tractus solitarii triggers swallowing.

Swallowing is a patterned motor activity generated by neurons located within the nucleus tractus solitarii (NTS). Previous experiments have shown that administration of excitatory amino acids within the NTS induces swallowing. The present study was undertaken to identify the receptor subtypes involved in this effect. Pressure microinjections of L-glutamate (10-100 pmol), quisqualate (0.1-10 pmol) and N-methyl-D-aspartate (NMDA, 0.1-10 pmol) were performed into the NTS of decerebrate rats. Glutamate and quisqualate microinjections elicited short series of swallows while NMDA microinjections induced long-lasting, rhythmic swallowing. Pretreatment with the selective NMDA antagonist, DL-2-amino-5-phosphonovalerate (50 pmol), almost completely suppressed the response elicited by NMDA (10 pmol) but did not induce a significant modification of swallowing triggered by either glutamate (25 pmol) or quisqualate (10 pmol). Pretreatment with 6-cyano-7-nitroquinoxaline-2,3-dione (50 pmol), a selective blocker of non-NMDA receptors, suppressed the swallows elicited by glutamate and strongly inhibited the response elicited by quisqualate microinjections. The same pretreatment induced only a slight modification of the swallowing elicited by NMDA. These data demonstrate that deglutition can be triggered by activating either NMDA or non-NMDA receptors localized within the NTS, and therefore suggest that both receptor subtypes may be involved in swallowing elicited under physiological conditions.

2-Amino-5-phosphonovalerate↗

PubMed1990

Coordination of deglutitive glottic closure with oropharyngeal swallowing.

The goals of this study were to quantify the temporal relationship between swallow-induced glottic closure and (a) signals of swallow initiation, such as hyoid bone movement, tongue base movement, and mylohyoid electrical activity; (b) pharyngeal peristalsis; (c) laryngeal elevation; (d) vestibular closure; and (e) oropharyngeal barium bolus transit. Eight normal subjects (age 20-30 yr) were studied by concurrent transnasal video laryngoscopy, pharyngeal intraluminal manometry, and submental surface electromyography. The manometric, electromyographic, and both video recordings were synchronized with one another using a specially designed event marker. Dry, 5-ml water, and 5-ml barium swallows were recorded. Frame-by-frame analysis of the video endoscopic recordings showed that deglutitive laryngeal kinetics consisted of vocal cord adduction associated with transverse approximation of the arytenoids followed by vertical approximation of arytenoids to the base of the epiglottis followed by laryngeal ascent and epiglottic descent. Onset of swallow-induced vocal cord adduction preceded the onset of hyoid bone movement, base of the tongue movement, and submental surface myoelectric activity by 0.33 +/- 0.04 (SE) s, 0.31 +/- 0.04 s, and 0.38 +/- 0.04 s, respectively. Onset of vocal cord adduction also preceded the initiation of peristalsis in the nasopharynx and its propagation to oropharynx and upper esophageal sphincter by 0.64 +/- 0.05 s, 0.82 +/- 0.05 s, and 1.08 +/- 0.04 s, respectively. The time between the onset of vocal cord adduction and their return to full opening was 2.2 +/- 0.09 s. It was concluded that (a) among events evaluated, vocal cord adduction is the initial event during the swallowing sequence; (b) laryngeal kinetics during deglutition have distinctive features, and their close coordination with other swallowing events suggests that they are an essential feature of the swallowing program; and (c) abnormal laryngeal kinetics or lack of coordination between the glottic closure mechanism and oropharyngeal bolus transport may have an important role in swallow-induced aspiration.

Adult↗

PubMed1991

Normal and disordered swallowing: new insights.

Swallowing is a complex sequence of integrated motor events which is programmed entirely within a 'pattern generator', the medullary swallow centre. The swallow is not a reflex but rather a programmed response which is only initiated given the right combination of cortical and peripheral sensory cues to the medulla. Interruption of these afferent pathways profoundly influences the ability to initiate a swallow. While the basic sequence of motor events that constitutes a swallow is constant, the temporal relationships among component events are modifiable according to the characteristics of the swallowed bolus. The pathophysiology of dysphagia can be categorized on the basis of dysfunction of one or more of seven broad mechanisms that make up the swallow: bolus preparation, lubrication, oral delivery, palatal closure, airway closure, pharyngeal propulsion and UOS opening. This mechanistic approach originates directly from the videoradiographic observations and provides a rational basis for treatment. Videoradiography is the single most valuable technique in the evaluation of oral pharyngeal dysphagia. Oesophagoscopy and laryngoscopy should be performed in most cases because small tumours in the region can mimic pharyngeal motor disorders and may be easily overlooked. Manometry is providing valuable physiological and pathophysiological information about swallowing but, as an adjunct to videoradiography, only provides additional important information in the minority of patients undergoing investigation.

Deglutition↗

PubMed2005

N-methyl-D-aspartate glutamate receptor mediates spontaneous and angiotensin II-stimulated ovine fetal swallowing.

BACKGROUND: In adult rats, N-methyl-D-aspartate (NMDA) receptors have been implicated in the central control of body fluid homeostasis, as intracerebroventricular (ICV) injection of NMDA receptor antagonists suppresses stimulated drinking behavior. Fetal swallowing occurs at a significantly higher rate as compared to adult drinking, contributing to amniotic fluid volume regulation and fetal gastrointestinal development. The aim of present study was to determine the role of central NMDA receptors in the modulation of fetal swallowing activity. METHODS: Eight time-dated pregnant ewes and fetuses were chronically prepared with fetal vascular and ICV catheters, electrocorticogram (ECoG), and esophageal electromyogram electrodes and studied at 130 +/- 1 days' gestation. Following an initial 2-hour baseline period (time 2 h), the NMDA receptor antagonist, dizocipline (1 mg), was injected ICV. At time 4 h, the dose of dizocipline was repeated, together with angiotensin II (AngII, 6.4 microg). Fetal swallowing was monitored for 2 hours after each injection. Four of these fetuses also received an identical control study (on an alternate day) in which dizocipline was replaced with artificial cerebrospinal fluid (aCSF). RESULTS: ICV dizocipline injection nearly abolished spontaneous fetal swallowing activities (0.6 +/- 0.1 to 0.2 +/- 0.1 swallows/min; P < .001). ICV AngII in the presence of dizocipline did not demonstrate a dipsogenic effect on fetal swallowing (0.1 +/- 0.1; P < .001). In the control study, ICV injection of aCSF did not change fetal swallowing activity (1.0 +/- 0.1 swallows/min), while ICV AngII resulted in a significant increase in fetal swallowing (2.0 +/- 0.1 swallows/min; P < .001). CONCLUSIONS: This study demonstrates that central NMDA-glutamate receptor-mediated activity contributes to the high rate of spontaneous and AngII-stimulated fetal swallowing. We speculate that reduced NMDA receptor expression within the forebrain dipsogenic neurons may account for observed differences in drinking activities between the fetus/neonate and the adult.

Angiotensin II↗

PubMed2005

Effects of injecting GABAergic agents into the medullary reticular formation upon swallowing induced by the superior laryngeal nerve stimulation in decerebrate cats.

The purpose of this study was to elucidate the role of the GABAergic system in the medullary reticular formation (MRF) in the control of swallowing. In acutely decerebrated cats (n = 12), swallowing was induced by electrical stimulation (0.3-6 V at 10-20 Hz for 10-20 s every minute) applied to the superior laryngeal nerve (SLN). The stimulus intensity was adjusted so that swallowing was induced two or four times during the period of the stimulation. Bicuculline, a GABA(A) receptor antagonist, was then injected (0.10-0.15 microl, 5 mM) into the MRF through a stereotaxically placed glass micropipette. In a total of 62 injections, 19 injections (30.6%) increased the frequency of SLN-induced swallowing when it was injected into the lateral part of the MRF corresponding to the nucleus reticularis parvocellularis (NRPv). In eight of the effective injections (42.1%) which increased the frequency of SLN-induced swallowing, SLN stimulation also induced coughing. With two injections, stimulation of the SLN-induced coughing but not facilitation of swallowing. On the other hand, an injection of 0.10-0.15 microl of 5 mM muscimol, a GABA(A) receptor agonist, into the NRPv decreased the frequency of SLN-induced swallowing. These results suggest that the NRPv neurons which are responsible for evoking swallowing are under the tonic inhibitory control of the GABAergic system.

Animals↗

PubMed2004

Dissociating the spatio-temporal characteristics of cortical neuronal activity associated with human volitional swallowing in the healthy adult brain.

Human swallowing represents a complex highly coordinated sensorimotor function whose functional neuroanatomy remains incompletely understood. Specifically, previous studies have failed to delineate the temporo-spatial sequence of those cerebral loci active during the differing phases of swallowing. We therefore sought to define the temporal characteristics of cortical activity associated with human swallowing behaviour using a novel application of magnetoencephalography (MEG). In healthy volunteers (n = 8, aged 28-45), 151-channel whole cortex MEG was recorded during the conditions of oral water infusion, volitional wet swallowing (5 ml bolus), tongue thrust or rest. Each condition lasted for 5 s and was repeated 20 times. Synthetic aperture magnetometry (SAM) analysis was performed on each active epoch and compared to rest. Temporal sequencing of brain activations utilised time-frequency wavelet plots of regions selected using virtual electrodes. Following SAM analysis, water infusion preferentially activated the caudolateral sensorimotor cortex, whereas during volitional swallowing and tongue movement, the superior sensorimotor cortex was more strongly active. Time-frequency wavelet analysis indicated that sensory input from the tongue simultaneously activated caudolateral sensorimotor and primary gustatory cortex, which appeared to prime the superior sensory and motor cortical areas, involved in the volitional phase of swallowing. Our data support the existence of a temporal synchrony across the whole cortical swallowing network, with sensory input from the tongue being critical. Thus, the ability to non-invasively image this network, with intra-individual and high temporal resolution, provides new insights into the brain processing of human swallowing.

Adult↗

PubMed2003

Effect of cortical masticatory area stimulation on swallowing in anesthetized rabbits.

The effects of stimulation of the cortical masticatory area (CMA) on swallowing evoked by superior laryngeal nerve (SLN) were studied in anesthetized rabbits. Electromyographic activity of the thyrohyoid, masseter, and digastric muscles and jaw-movement trajectories were recorded to monitor rhythmic jaw movements (RJMs) or swallowing. A systematic series of microelectrode penetrations within the CMA was made for each animal, and the effects of CMA stimulation on swallowing were tested by comparing the number of swallows evoked by stimulation of the CMA alone, the SLN alone, and simultaneous stimulation of the SLN and CMA. A significant facilitatory effect was observed in 49 (52%) of the 95 CMA loci tested. No significant effect was noted in the remaining 46 loci. Three different types of RJMs were evoked by CMA stimulation, and topographical organization was noted among CMA loci that evoked different types of RJMs. A high percentage of (77%) the CMA loci that evoked RJMs with a prominent horizontal excursion of the jaw facilitated swallowing and was located in the posterolateral and deep part of the CMA. A majority (88%) of the CMA loci that evoked RJMs with small circular jaw movements did not affect swallowing and was located in the anteromedial and shallow part of the CMA. The facilitatory effect of CMA stimulation on swallowing remained even after removal of peripheral sensory inputs by means of deafferentation of infraorbital and inferior alveolar nerves. Results suggest the existence of facilitatory descending pathways to the swallowing center from particular intracortical loci of CMA.

Anesthetics, Inhalation↗

PubMed1998

Gut feelings about recovery after stroke: the organization and reorganization of human swallowing motor cortex.

Swallowing problems can affect as many as one in three patients in the period immediately after a stroke. In some cases this can lead to serious morbidity, in particular malnutrition and pulmonary aspiration. Despite this, swallowing usually recovers completely in the vast majority of patients within weeks. This impressive propensity for recovery is likely to relate to how the area of the motor cortex concerned with swallowing is organized and then reorganized after cerebral injury. Recent studies have indicated that swallowing has a bilateral but asymmetric inter-hemisphere representation within motor and premotor cortex. Damage to the hemisphere that has the greater swallowing output appears to predispose that individual to swallowing problems. However, because there is additional substrate for swallowing in the undamaged hemisphere, the capacity for compensatory reorganization in the contralateral motor cortex might be increased, leading to a greater likelihood of recovery. Swallowing might be an excellent system for studying cortical plasticity, and might prove useful in the development of new therapies aimed at accelerating reorganization in the undamaged hemisphere after unilateral cerebral injury.

Adaptation, Physiological↗

PubMed2002

Objective assessment of swallowing dysfunction and aspiration after radiation concurrent with chemotherapy for head-and-neck cancer.

PURPOSE: To objectively assess swallowing function after an intensive chemoradiation regimen for locally advanced head-and-neck cancer and to assess the clinical implications of swallowing dysfunction. PATIENTS AND METHODS: Twenty-nine patients with nonresectable Stage IV head-and-neck cancer participated in a Phase I study of radiation, 70 Gy/7 weeks, concurrent with weekly gemcitabine. Because of a high rate of mucosal toxicity, reduced drug doses were delivered to subsequent patient groups: 300, 150, 50, and 10 mg/m(2)/week. Twenty-six of these patients underwent prospective evaluation of swallowing function with videofluoroscopy and esophagogram. Studies were performed pretherapy, early post-therapy (1-3 months), and late post-therapy (6-12 months). RESULTS: Complete tests were performed pretherapy in 22 patients, early post-therapy in 20, and late post-therapy in 13. Twenty-five patients had at least one post-therapy study. Post-therapy dysfunction was characterized by reduced inversion of the epiglottis, delayed swallow initiation and uncoordinated timing of the propulsion of the bolus, opening of the cricopharyngeal muscle, and closure of the larynx, all of which promoted aspiration during and after the swallow. In addition, reduced base-of-tongue retraction with reduced contact to the posterior pharyngeal wall and incomplete cricopharyngeal relaxation resulted in pooling in the pyriform sinuses and vallecula of residue, which was frequently aspirated after the swallow. Post-therapy aspirations were typically "silent," eliciting no cough reflex, or the cough was delayed and noneffective in expelling the residue. Aspiration was observed in 3 patients (14%) in the pretherapy studies, in 13 (65%) in the early post-therapy studies, and in 8 (62%) in the late post-therapy studies (aspiration rates post-therapy vs. pretherapy: p = 0.0002). Six patients had pneumonia requiring hospitalization 1-14 months after therapy (median: 2.5 months), being the likely cause of death in 2 patients. Five cases of pneumonia occurred among 17 patients who had demonstrated aspiration in the post-therapy studies, compared with no cases of pneumonia among 8 patients who had not demonstrated aspiration (p = 0.1). Of the 4 patients who had not undergone any post-therapy study, 1 developed pneumonia. Mucositis scores, prolonged tube feeding, presence of tracheostomy tube, and gemcitabine doses were not found to be related to aspiration or pneumonia risk. CONCLUSIONS: After intensive chemoradiotherapy, significant objective swallowing dysfunction is prevalent. It promotes aspiration, which may not elicit a cough reflex and may be associated with pneumonia. Aspiration pneumonia may be an underdocumented complication of chemoradiotherapy for head-and-neck cancer. Future studies should examine whether routine post-therapy videofluoroscopy and training aspirating patients in safe swallowing strategies can reduce this risk.

Combined Modality Therapy↗